1. Field of the Invention
The present invention relates to apparatus for inspecting powder granules and more particularly to a powder granule inspection apparatus that samples powder granules (such as powders, pellets, granules and so on) that flow through an online conveyor tube so as to automatically conduct inspection for foreign particles contained therein and to remove the foreign particles, and that is arranged to shorten the time from the sampling of powder granules to the inspection thereof as much as possible so that the inspection results become available within a short period of time.
2. Description of the Prior Art
In a known apparatus, a certain amount of the sampled powder granules is accumulated in a hopper, from which a small amount of the powder granules is removed and supplied to the top of a rotating table. The moving powder granules are picked up by a photosensing device and the size and number of foreign particles therein are detected. The ratio of the foreign particles relative to the amount of powder or granule in the hopper is then determined relative to a predetermined standard. In this case, the certain amount of powder granules was set at relatively large amount (such as about 500 grams).
However, this prior art apparatus does not conduct the inspection during the time that the certain amount of powder granules is being accumulated in the hopper. Therefore a long period of time is required from the time inspection is initiated until it is completed. This causes a delay in the availability of the inspection result so that when powder granules flowing through an online conveyor contain excessive amount of foreign particles it will only be possible to detect the foreign particles after a large amount of such powder granules have entered the production line and their removal would be inconvenient.